nr pare dintr-un interval_dani

#include <iostream>

using namespace std;

int main()
{
    int a,  b, n;
    cout<<"Introduceti capetele intervalului[a,b]:";
    cin>>a>>b;
    n=b-a+1;
    if(n%2==0)
        cout<<"Exista "<<n/2<<" nr pare in inerval";
    else
        if(a%2==0)
        cout<<"Exista "<<(n+1)/2<<" nr pare in inerval";
        else
        cout<<"Exista "<<(n-1)/2<<" nr pare in inerval";

    return 0;